1. Field of the Present Invention
The present invention relates to a vehicle equipped with an electric motor that can output power to a drive shaft that is coupled to a drive wheel. The present invention also relates to a control method of the vehicle.
2. Description of the Related Art
A conventional electric vehicle has been known to determine if a driving motor is locked. When it is determined that the motor is locked, a driving force of the motor is set to a limited value that is lower than a normal value that corresponds to a required driving force. When it is determined that the motor lock is canceled, the driving force is returned to the normal value (see Japanese Patent Application Publication No. 2007-329982 (JP-A-2007-329982), for example). This electric vehicle is designed to have a smaller rate of change of a driving force in proportion to lower inclination of a road surface when the driving force of the motor is returned from the limited value to the normal value, thereby suppressing fluctuation in driving torque upon vehicle start-up. Meanwhile, the electric vehicle is also designed such that the rate of change of the driving force is reduced inversely with an increase in inclination of the road surface, when the driving force of the motor is changed from the normal value to the limited value. Thus, it is possible to maintain a constant distance of rearward movement of the vehicle regardless of the inclination of the road surface when it is determined that the motor is locked.
However, as in the above conventional electric motor, even if the rate of change of driving force is reduced inversely with the increase in inclination of the road surface, when the driving force of the motor is changed from the normal value to the limited value, the vehicle moves rearward to a certain degree at hill start, apart from the intention of a driver. Consequently, it is difficult to prevent passengers from feeling a sense of discomfort.